We present a pressured mediated tunable optofluidic dye laser with novel cavity. The dye laser chip was fabricated with Polydimethylsiloxane (PDMS) via replica molding and has none nano-features. It comprises a liquid waveguide and micro-scale air-gap chambers which function as mirrors to provide feedback. The lasing wavelength was determined by the interference of the reflected beams from the two PDMS-air interfaces of the air-gap chamber acting as Fabry-Perot etalon, while the tuning was realized by varying the width of the air-gap by applying air pressure. The lasing with linewidth of 3 nm and tuning range of 14 nm was demonstrated. © 2010 Copyright SPIE - The International Society for Optical Engineering.